The invention relates to a motor vehicle with an air-conditioning system that has an air-conditioning compressor in which the compressor throughput is regulated by adjusting the piston stroke. The adjustment of the piston stroke is accomplished by controlling the drive-chamber pressure of the compressor by means of a control valve. The air-conditioning system has a control device using characteristic curve fields or data arrays. The combustion engine of the motor vehicle is equipped with an electronic engine-management device.
Motor vehicles with air-conditioning systems meeting the foregoing description belong to the known state of the art. They have air-conditioning controllers performing a quasi-static control based on characteristic fields or arrays. These state-of-the-art system have a problem in situations where the torque reserve of the combustion engine is inadequate, for example if the vehicle is to be accelerated abruptly from a state where the engine is generating only an idling-level torque or a part of its capacity-level torque, where the torque delivered by the engine is needed to accelerate the vehicle. As the engine is unable to supply the additional torque for the air conditioner, and the latter cannot be regulated to a lower torque level with a sufficiently fast response by the conventional control devices, the additional amount of torque consumed by the air-conditioning compressor may cause the engine to stall or will in any case cause a sluggish acceleration of the vehicle. Conversely, with a sudden increase in the available engine torque, the throughput of the air-conditioning compressor cannot be turned up by the control system with a fast dynamic response.